Diarrhea (or 'the runs') is defined as passing of loose stools and/or increase in frequency of bowel movement. Surveys show that more than 3 bowel movements a day exceeds what is normal and is therefore considered diarrhea. Diarrhea is a common problem; in America the average adult experiences at least one bout of diarrhea a year, and children 2 bouts. Acute diarrhea usually lasts one to two days and clears of its own accord without treatment. Chronic diarrhea is defined as diarrhea that lasts at least 3 weeks. It is a more serious problem as it can result in dehydration and may be an indication of an underlying disease. Dehydration means the body lacks the necessary fluids to function properly which is particularly dangerous in old people and children.

What Causes It?

The most common type, acute diarrhea is usually related to a viral, bacterial or parasite infections.

Viral Infection
There are lots of viral infections which can cause diarrhea, the most common being viral hepatitis, herpes simplex, Norwalk virus and rotavirus. Viral gastroenteritis, also known as 'stomach flu' usually results in diarrhea as well as vomiting, and is most commonly caused by the rotavirus. In general symptoms of viral gastroenteritis start within 2 days of infection and can last for up to 10 days. It is contagious and can spread through close contact with infected people or it can be passed through contaminated food and drinks prepared by an infected person.

Bacterial Infection
Many types of bacteria which cause diarrhea are passed through contaminated food or drinks. The most common bacteria include E.coli, salmonella, shigella and campylobacter. Most bacterial infections are not serious and clear within a few days without treatment. Others may cause trouble for certain risk groups, namely the young and the old. Some strains of E.Coli secrete a toxin which can be life threatening. Other strains can cause traveler's diarrhea, a milder infection. E.Coli can spread via contact with an infected person, or by consuming contaminated foods such as an undercooked burger or unwashed fruit. Salmonella bacteria cause an estimated one to five million cases of diarrhea a year in America. This type of bacteria is a major cause of food poisoning and is typically found in eggs or undercooked chicken. Shigella bacteria cause nearly 160 million cases of diarrhea worldwide every year.

Parasite Infections
Parasites can enter the body by consuming contaminated foods or drinks and then settle in the digestive system. The most common parasites are Giardia lamblia, Cryptosporidium and Entamoeba histolytica. The Giardia parasite spreads from person to person and via contaminated water. As it is resilient to chlorine it can be contracted through swimming in infected pools, streams or lakes. Cryptosporidium causes watery diarrhea which can last 2 weeks or more and is the most likely culprit for break-outs in public places. An infection of Entamoeba histolytica is known as amoebiasis. It is more common in those living in tropical climates or in poor sanitary conditions, although there are about 500 reported cases in New York City alone every year.

Food Intolerances
Some people who are unable to digest certain ingredients may experience a bout of diarrhea if they ingest food containing those ingredients. Most common intolerances are lactose, wheat, gluten and artificial sweeteners (mannitol & sorbitol). Some people have problem with fructose found in fruit as well as caffeine products.

Reaction to Drugs/Medications
Side effects of some medications may cause acute diarrhea. The most likely culprits are antibiotics, blood pressure lowering tablets (beta blockers and ACE inhibitors) and medications containing quinidine (found in drugs to control irregular heartbeats or arrhythmias).

Chronic diarrhea on the other hand is generally related to an underlying condition such as:
• Irritable Bowel Syndrome (IBS)
• Inflammatory Bowel Disease (IBD)
• Crohn's Disease, a form of IBD
• Colitis, a swelling of the large intestines which causes frequent bowel movements, bloating and chills.

What Are The Symptoms?

Frequent bowel movements may be accompanied by:

• Abdominal cramping or pain
• Bloated stomach
• Nausea
• Fever, depending on the cause, as well as blood in the stool
• Dehydration, associated with chronic diarrhea. Signs of dehydration include the need to urinate less frequently, dark colored urine, dizziness, fatigue, thirst and dry skin. Anyone who experiences these symptoms should instantly contact their doctor.

When Should I Call a Doctor?

A bout of diarrhea is generally not harmful and often disappears within 48 hours. However, do call a health care provider if you experience any of the following symptoms:

• Diarrhea for more than two days.
• Dehydration.
• Severe abdominal or rectum pain.
• A fever of 102 degrees or over.
• Stools which contain blood or are black in color. See reasons for seeing a doctor for more general advice.

How Is The Cause Identified?

Diagnostic tests may include:

Medical history and physical examination: Your doctor may ask about bowel movements, dietary habits and check for signs of illness. Stool Culture: You may need to bring a stool sample for lab tests of bacteria or parasites. Blood Test: This can help rule out any underlying conditions.Sigmoidoscopy: A flexible tube with a small camera is inserted through the rectum. It is used for investigating the large intestine for signs of bleeding, abdominal pain and colon cancer.Fasting Test: If a food intolerance is a suspected cause, you may be asked to avoid the food to see if this stops the diarrhea. Colonoscopy: A colonoscopy is similar to a sigmoidoscopy but the doctor can view the entire colon.

What Is Functional Diarrhea?

If diarrhea lasts longer than 3 weeks it is classified as chronic. If tests have been carried out and no cause can be identified it may be labeled ‘functional diarrhea’. Medics use the term 'functional' to describe problems or symptoms where they find no clinical or anatomical abnormalities. So for example, there is functional bowel disorder, functional abdominal bloating and functional constipation. Functional diarrhea is usually chronic meaning is occurs frequently over a period of months to years.

How Is Diarrhea Treated?

In most instances, diarrhea does not need treatment and clears within 48 hours. Some people use over the counter remedies such as Pepto-Bismol, Kaopectate and Imodium to relieve symptoms, particularly if they also have cramping. If you do take antidiarrheal medication make sure you discuss any other medications you are taking with your pharmacist to ensure they do not interact. However, if blood occurs in the stool, it may be a sign of a bacterial or parasite infection. This requires treatment with an antibiotic. See also, how to treat diarrhea.

What Dietary Changes Should I Make?

If you have a bout of diarrhea, avoid greasy foods and foods high in fiber. Instead choose soft bland foods like rice, boiled potatoes, toast, baked fish or chicken and bananas. The BRAT diet is often suggested by doctors for people with tummy upsets as it does not irritate the stomach. BRAT stands for Bananas, Rice, Applesauce and Toast. It includes 'binding' foods which make the stool stick together and bananas which are high in potassium helping to replace nutrients lost in diarrhea.

Caffeine has a laxative effect in many people, so if you are a big coffee or cola drinker, try cutting it out until the symptoms pass. If you notice that you are more prone to diarrhea during the summer when fresh fruits are more available, it might be worth moderating your intake.

Traveler's Diarrhea - What Is It?

Traveler's diarrhea, usually a mild form of diarrhea, happens when a person consumes food or water containing a bacteria or parasite while traveling abroad. If you do travel outside of America take the following preventative precautions:

• Do not drink tap water or brush your teeth in it.
• If you buy bottled water, make sure the seal is still intact.
• Say No to ice in your drinks.
• Avoid fruits, salads and raw vegetables.
• Do not eat rare or uncooked fish or meat.
• Avoid food from street vendors.

Some people may experience constipation when traveling, and this if often linked to a change in eating patterns and/or diet.

Is Diarrhea During Pregnancy Common?

Constipation in pregnancy is a more common complaint, particularly in the first trimester. However, diarrhea is also relatively common and is probably related to hormone and dietary changes. A bout of diarrhea for one or two days is not something for concern, unless accompanied by nausea or vomiting which can cause dehydration. Many women experience diarrhea just before childbirth which may be the body's way of clearing the system in preparation for the event.